. Which of the following are not state functions
(a) (I), (II) and (III)
(b) (II) and (III)
(c) (I) and (IV)
(d) (II), (III) and(IV)
Correct Option is : (b)
State functions or state variables depend only on the state of the system and not on the path taken by it.
For example, internal energy of a body is given by q+w, change in internal energy between A and B will be the same when either of paths are taken.
Path function depends on the path followed during a process. Work and heat are path functions.
For example, considering the same graph, work done by a body is given by area under p-v graph along v. Thus work done in path I will be different from that of path II. Therefore work is a path function.